Effect of natural ventilation and evaporative cooling on greenhouse-microclimate with tomato crop inside | |
| Author | Meherunnahar, Mst. |
| Call Number | AIT Thesis no.AE-06-04 |
| Subject(s) | Greenhouse gardening Tomatoes--Environmental aspects |
| Note | A thesis submitted in pa1iial fulfillment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AE-06-04 |
| Abstract | Experiments were conducted in a greenhouse equipped with a fan and pad cooling system in which tomatoes were. Temperature and humidity were measured along the greenhouse as a function of height and space. Effects of ventilation on the temperature and humidity gradients and on the heat fluxes were examined within the greenhouse. It was shown that in fan and pad cooling greenhouse the inside air temperature remained most of the days lower than ambient temperature due to the effect of cooling and air flow. The main temperature gradient, in this experiment, was observed in the vertical direction from bottom to top and its absolute value decreased with an increase in ventilation rate. An opposite behavior was observed in naturally ventilated greenhouse. Air temperature inside the greenhouse was higher in natural ventilated greenhouse. For all the days it was higher than ambient temperature. For both, fan and pad cooling and the natural ventilation, ventilation affected the temperature difference between inside and outside the greenhouse; decreasing the air temperature further as the ventilation rate increased. In both systems, the specific humidity within the greenhouse was always higher than the ambient specific humidity. As expected, higher values were observed in fan and pad cooling greenhouse. Similar to the temperature gradients, larger specific humidity gradients in fan and pad cooling were observed in vertical direction, which decreased with increase in ventilation rate. The temperature difference affected the total yield. Temperature was lower near pad side and it was higher near fan side in evaporative cooling greenhouse. For natural ventilated greenhouse it was higher near net side and lower near fan side. Total yield was significantly different for both greenhouses. It was 30-40% lower in fan and pad cooling greenhouse comparing to natural ventilated greenhouse. Plant height, stem diameter and number of flowers were also lower in fan and pad cooling greenhouse but fruit quality (marketable fruits, color, moisture content, fruit diameter, Brix and pH) of both greenhouses was not significantly different. Overall the evaporative cooling greenhouse may not be positive effect for crop growth, yield and fruit quality |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AE-06-04 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Salokhe, Vilas M. |
| Examination Committee(s) | Jayasuriya , H. P.W. ;Singh, Sahdev ;Max, Johannes ; |
| Scholarship Donor(s) | Norway Government Scholarship, NORAD; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2006 |